This invention relates to power transmission apparatus comprising a hydro-kinetic torque converter combined with gearing and is especially applicable to the apparatus as described in the specifications of British Pat. Nos. 1,199,521 and 1,347,045.
The apparatus claimed in British Pat. No. 1,347,045 comprises an input shaft, an impeller connected to the input shaft, an output shaft, an output turbine connected to the output shaft, a circulatory turbine disposed in the flow path between the impeller and output turbine, a first gearing and a second gearing, said first gearing connecting the circulatory turbine to the impeller; said second gearing being connected with the first gearing, the output shaft and a stationary part; whereby the first gearing can transmit driving torque from said circulatory turbine to said impeller, said driving torque increased by the second gearing is transmitted from the circulatory turbine through said first gearing to the output shaft and reaction torque is imparted to said stationary part, so that the said circulatory turbine will always rotate when the impeller rotates and in the same direction but at a speed less than that of the impeller at a lower speed part of the range of speeds of the output shaft and at a speed greater than that of the impeller at a higher speed part of said range. For reversing a separate reversing gear was attached to the rear end of the apparatus.
It is often required to provide means for reversing the direction of the output shaft and also to provide means for increasing the braking effect on the output shaft when the converter output is rotating in a forwards direction, but when the drive to the converter is reversed and applied to the shaft which normally acts as the output shaft.
For example when a converter is used in a motor vehicle it is necessary to be able to "reverse" the vehicle and desirable to provide output shaft braking when descending a steep hill.
Means to achieve these operations can be bulky and complicated and may cost as much to manufacture as the torque converter.